How do I let people download a file from my page?

Recently I signed up with a pharmacy: affiliate progams that helps people get prescriptions cheaper..They allow for files to be put on a webpage..but how do I make this file ( a list of medications and prices) downloadable from my site?

The only way for you to get credit for the prospective customer is through your referral id. If they download something from your site that isnt in someway connected with the pharmacy, the pharmacy has no way you referred them